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Silicon Sea: Leg 83
From: Dan Hogan
Date: 2002 Sep 19, 08:00 -0700
From: Dan Hogan
Date: 2002 Sep 19, 08:00 -0700
Chart(s): Plotting Sheets
Sight Reduction and
Dead-Reckoning problem Leg 83 091902 Test your knowledge!
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We are bound for a Hawaii landfall waypoint at(19d 30.0'N 154d 45.0'W).
We had a RUNNING FIX on 16/07/2001 @ 01:44:36UT(18d 37.2'N 152d 13.6'W).
The highest point on the island of Hawaii that should be visible to us is
the Mauna Loa Volcano (19d 30.0'N 155d 36.0'W) at a height of 4169 meters.
1) At what distance should the Silicon Sea navigator expect to be able to
see the top of Mauna Loa(19d 30.0'N 155d 36.0'W) on the horizon?
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Var 10dE Dev 1.0dE. Speed 10 Kts, Current Set 095d, Drift 0.7 Kts.
2) What is the Compass Course(CC)/Course-to-Steer toward Mauna Loa, at
(19d 30.0'N 155d 36.0'W) from our RUNNING FIX(18d 37.2'N 152d 13.6'W)?
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3) What Time Zone are we in?
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Since our RUNNING FIX 16/07/2001 @ 01:44:36UT(18d 37.2'N 152d 13.6'W), we
have run an elapsed distance of 140 Nmi on a TC 290.0d. At this time we
sight Cape Kumukahi(19d 30.0'N 154d 45.6'W), which we must round to head
>for Hilo, Hawaii, our port of entry. Speed 10 Kts.
4) What is our DR position at our 140 Nmi point?
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>Use 19d 30.0N'N 154d 41.6'W for the Distance Off calculation to clear
Cape Kumukahi by 4 Nmi abeam. Speed 10.0 Kts, Var 10dE Dev 1.0dE. Current
Drift 0.4 Kts Set 270d.
>5) What is the Compass Course (CC) we must steer from our DR position?
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Our port of entry will be at Hilo, Hawaii (19d 44.0'N 155d 04.0'W).
>6) What is the distance from Cape Kumukahi D.O. Point(19d 30.0N'N
154d 41.6'W) to the entry point(19d 44.0'N 155d 04.0'W) at Hilo ?
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7) What is the Zone Time(ZT) ETA at the Hilo entry point?
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NOTE:
Lat & Lo = XXd XX.X', Date=DD/MM/YY, HE 9 Feet, Index correction
-2.5', Time hh:mm:ss in UT,unless otherwise stated. Silicon
Sea II is a 34,000 lb(15.40t) displacement sailing vessel, 48' 3"
(14.70m) LOA. 39' (12.00m) LWL; Cutter rigged. Can tack to 45d.
Water Tanks = 220 gal(1000 ltrs). Fuel Tanks = 155 gal(700 ltrs).
Fuel consumption .675 gal/Hr at 8.5 Kts. DR(Ded-Reckoning)=position
by sailings, EP(Estimated Position)=DR+current affect. Dist to
Horizon: Nmi = SQRT HE@mtrs x 2.07; Nmi = SQRT HE@ft x 1.17.
PLEASE respond with your results and thinking on these exercises to
the NAVIGATION list at large. If you have questions or problems, A
lot of folks on the list are knowledgeable and willing to help. Any
questions or doubtful areas will be responded to promptly. Let us
hear from you soon!
Good Navigating!
-=The Navigation List Working Group=-
Peter Smith - Smith_Peter@emc.com
Mike Wescott - wescott_mike@emc.com
Dave Weilacher - daveweilacher@earthlink.net
Tony Capiello - anthony.cappiello@baesystems.com
Richard Berkowitz - richdberko@aol.com
Dan Hogan - dhhogan1@earthlink.net
Dan Hogan WA6PBY
C27 "Gacha"
dhhogan1@earthlink.net
Nav-L Page: http://www.wa6pby.com
